At the beginning of the game when you first come across a little sister, rescue her. And then in the next mission when you get the opportunity to come across more, make sure you rescue them all. You will receive a gift on the second mission in a teddy bear. One of the gifts is a plasmid to hypnotise Big Daddies. It's important you have this as it will become a lot easier to go through the game using this plasmid. Just make sure you have the space for it, and make sure you use it wisely whenever you come across a Big Daddy.

You got telekinesis? good. Stand a goodly distance away from him so he doesn't smack you and just hurl things at him while dodging his bullets. Make sure you hurl the bombs that he throws at you right back. Those are the killers.

Getting the achievement for beating the game on hard may take some time, but not nearly as much as beating it on hard without dying. But you know you want those 100points and to look cool saying you've done it. Max out the shotgun ASAP and work on the machine gun from there. Only 2 guns you really need through the whole game. Focus heavily on Health/Eve upgrades whenever possible to keep up with the fights. Most of the plasmids are useless minus shock/fire. Shotgun for close ranged fights or for a quick head shot, machine gun for groups charging at you or getting shots in at a distance. Also both weapons work very well on big daddies with armor piercing bullets and exploding shells. Those weapons and upgrades combined with a few dozen saves every so often and being mindful of what you're doing, beating the game on hard without dying shouldn't be too much of an issue.

Good luck, you know you want to do it.

First of all know when to use First Aid Kits and Eve Hypos, there are times you'll need Health and Eve badly in the middle of a fight, but you could save your med kits and hypos for later by finding nearby food items and hacking machines.

Secondly when you get to Arcadia research the Houdini Splicer as soon as possible, this will reward you with Natural Camoflague which will give you a huge advantage.

Third thing on the list is pattern recognition, everything in th game is set to happen at a specific time and place, forget what the developers told you about the game, the only truly roaming enemies are the Big Daddies and they're initially neutral, remembering where you stand when certain enemies appear will let you know how to avoid being seen even without that Tonic, with the Tonic it's even easier.

Item number four, Electrobolt and Telekinesis ARE the only Plasmids you actually need to complete the game with, however there exist blocks of Ice that the Inferno Plasmid can be very useful in removing, some of them contain Eve Hypos, remembering which ones do this can be useful, also the Hypnotise and Frenzy Plasmids are worth a slot due to how helpful they can be.

And last but not least, your main weapons will most likely consist of the Revolver and Shotgun, these will usually end up fully upgraded before any other, the Crossbow and Grenade Launcher can both be used to lay down traps to make killing Big Daddies easier, in a fight against a normal Splicer however you'll either be using the Revolver or Shotgun due to their excellent balance of fire rate, damage and reloading speed, obviously headshots are the way to go and you'll need to attack each enemy with it's weakness this is what the Camera is for, get some action shots.

Instead of buying health packs for 10 dollars each at Health Stations, why not try smashing in the machines with your wrench? After a few good hits, up to three health packs should be lying on the ground waiting for you to grab them.

Gambling is a great way to make some money, provided that you already have a bit of money to start with.

Once you find a slot machine, it costs $10 to pull the arm, you win $25 if you get three of a kind, $50 if you get two dollar signs ($), and if you get three dollar signs (jackpot) you win $250 as well as unlocking an achievement worth 10 points.

You cannot play more than one slot machine at once.

There are two possible endings for BioShock that depend on how you treated little sisters throughout the game. If you choose to "harvest" more than one little sister, you will get the bad BioShock ending. If, however, you "harvest" no more than one little sister but "rescue" the others, you will get the good BioShock ending.

The following tip only works with the Crossbow and the Grenade Launcher:

When shooting either of the weapons, you can quickly reload by pressing the left trigger, then immediately after pressing the right trigger.

About halfway through the game, you meet Sander Cohen, this crazy artist dude. When you finish the level, you can just leave him or kill him. If you kill him at that point, you can't get one of the Achievements "Find Cohen's Room." A while later you will stumble onto Cohen's apartment. If he's alive, two Splicers will be dancing in the main room, with Cohen watching from his locked private room. Kill the Splicers and then Cohen comes out to fight you, thus unlocking the door and allowing you to earn the Achievement.

A few cheats on this site say "Kill Cohen and photograph him for the 'Irony' achievement, then reload the game and let him live."

Well, I'm here to tell you that you can get both achievements without going back in time. just let him live, and when you reach his apartment, kill the dancing splicers, then when Cohen gets angry, kill him and take his photo. Then you can skip merrily up the stairs to the Power to the People machine. Happy hunting, little moth.

Before doing anything else in a room, use a blast of the Electric Shock Plasmid to disable the Security Drones shortly. Run up to them within five seconds and hack away! They [the security drones] should be on your side for any fights after this.

Gene Tonics
Physical Tonics

Bloodlust: Available at U-Invent machines, starting in the Fort Frolic area.
Effect: You gain small amounts of Health and EVE when inflicting damage with the Wrench.

Booze Hound: Available at U-Invent machine, starting in the Fort Frolic area.
Effect: Drinking alcohol restores a small amount of EVE, rather than draining it!

EVE Link: Available in a Gatherer's Garden vending machine, starting in the Medical Pavillion area.
Effect: First Aid Kit's give you EVE.

EVE Link 2: On the ground in the Farmer's Market.
Effect: First Aid Kit's give a large amount of EVE.

Extra Nutrition: Available in a Gatherer's Garden vending machine, starting in the Neptune's Bounty area.
Effect: You gain a little extra health from Snacks and Bandages.

Extra Nutrition 2: Downstairs inside Sinclair Spirits, in the back corner of the water-filled room.
Effect: You gain extra Health and Snacks and Bandages.

Extra Nutrition 3: Receive when reaching Research Level 4 with Spider Splicer.
Effect: You gain a great deal of Health from Snacks and Bandages.

Hacker's Delight: In the Eternal Flame Crematorium. Activate the Furnace Control to cremate the corpse on the tray.
Effect: Every time you hack something, you gain a little Health and EVE.

Hacker's Delight 2: Available at U-Invent machines, starting in the Fort Frolic area.
Effect: Every time you hack something, you gain Health and EVE.

Hacker's Delight 3: On the desk next to the Rosie Helmets in the Fallsafe Armored Escorts wing.
Effect: Every time you hack something, you gain a large amount of Health and EVE.

Medical Expert: On the ground in the Lower Wharf.
Effect: First Aid Kits give you 20% more Health.

Medical Expert 2: Inside Fort Frolic, but only after completing Cohen's Masterpiece.
Effect: First Aid Kit's give you 40% more Health.

Medical Expert 3: Near the toilets in Dr.Suchong's Clinic on the second florr of Artemis Suites.
Effect: First Aid Kit's give you 60% more Health.

Natural Camouflage: Receive when reaching Research Level 2 with Houdini Splicer.
Effect: When standing still, you become invisible.

Scrounger: Receive when reaching Research Level 2 with Leadhead Splicer.
Effect: When searching containers or corpses, you can search again to get different loot.

Security Evasion: On the ground in the Lower Concourse of Arcadia.
Effect: Security Cameras and Turrets take 2 seconds longer to see you.

Security Evasion 2: On the desk in the Lower Heat Loss Monitoring, right next to the Audio Diary.
Effect: Security Camerad and Turrets take 4 second longer to see you.

Sportboost: Receive when reaching Reseach Level 2 with Thuggish Splicer.
Effect: You move and swing the Wrench faster. Movement is speed increased 10% and Wrench swing speed is increased by 25%.

Sportboost 2: Receive when reaching Reseach Level 4 with Thuggish Splicer.
Effect: You move and swing the Wrench much faster. Movement is speed increased 20% and Wrench swing speed is increased by 50%.

Engineering Tonics

Alarm Expert: On the balcony in the Fleet Hall Theatre. Jump from one balcony to the other to get it.
Effect: Up to 2 fewer alarm tiles when hacking.

Alarm Expert 2: In the Live Subject Testing area of Point Prometheus. It's on a filing cabinet.
Effect: Up to 4 fewer alarm tiles when hacking.

Clever Inventor: On the desk in Suchong's Apartment in Olympus Heights.
Effect: Inventing items require 1 fewer of each component (mininum of 1).

Focused Hacker: In the entrance to Fontaine Fisheries, frozen in the ice near the pneumatic tube.
Effect: Up to 2 fewer overload tiles when hacking.

Focused Hacker 2: Hestia Fourth Floor, on the desk in the corner of the room near the safe.
Effect: Up to 2 fewer overload tiles when hacking.

Hacking Expert: On the desk inside to the Reseach Laboratories.
Effect: All hacks have 1 fewer alarm tile and 1 fewer overload tile.

Hacking Expert 2: Available in a Gatherer's Garden vending machine starting in the Fort Frolic area.
Effect: All hacks have 2 fewer alarm tiles and 2 fewer overload tiles.

Prolific Inventor: Rescue 18 Little Sisters to receive this tonic as a reward from Tenenbaum.
Effect: Whenever you invent an item, you get twice as many as normal.

Safecracker: Rescue 6 Little Sisters to receive this tonic as a reward from Tenenbaum.
Effect: When hacking safes and combination locks, there are up to 2 fewer alarm and overload tiles, 1 fewer accelerate tile, and 3 added deceleration tiles. The flow speed is reduced by 0.5 seconds per tile.

Safecracker 2: In the Autopsy room in the downstairs of the Little Wonders Educational Facility.
Effect: When hacking safes and combination locks, there are up to 2 fewer alarm and overload tiles, 2 fewer accelerate tile, and 3 added deceleration tiles. The flow speed is reduced by 1.0 seconds per tile.

Security Expert: In the Twilight Fields funeral area. It is on a shelf in the mortuary room.
Effect: When hacking Turrets, Security Bots, and Security Cameras, there are up to 2 fewer alarm and overload tiles, 1 fewer accelerate tile, and 1 added deceleration tile. The flow speed is reduced by 0.5 seconds per tile.

Security Expert 2: Obtained by reaching Research Level 2 with the Security Bot.
Effect: When hacking Turrets, Security Bots, and Security Cameras, there are up to 4 fewer alarm and overload tiles, 2 fewer accelerate tile, and 3 added deceleration tile. The flow speed is reduced by 1.0 seconds per tile.

Shorten Alarms: Available in a Gatherer's Garden vending machine starting in the Arcadia area.
Effect: Length of security alarms is reduced by 20 seconds.

Shorten Alarms 2: On a walkway in the lower Geothermal Core area of Hephaetus.
Effect: Length of security alarms is reduced by 40 seconds.

Speedy Hacker: In the corner of the room in Painless Dental.
Effect: Flow speed is reduced by 1.5 seconds per tile when hacking.

Speedy Hacker 2: Available in a Gatherer's Garden vending machine starting in the Olympus Heights area.
Effect: Flow speed is reduced by 3.0 seconds per tile when hacking.

Combat Tonics

Armored Shell: Avaiable in a Gatherer's Garden vending machine starting with the Medical Pavillion area.
Effect: Reduces piercing and bludgeoning damage by 15%.

Armored Shell 2: Rescure 15 Little Sister's to receive this tonic as a reward from Tenenbaum.
Effect: Reduces piercing and bludgeoning damage by 25%.

Armored Shell 3: On a desk in the secret crawlspace office in the Lower Workshops.
Effect: Reduces piercing and bludgeoning damage by 30%.

Damage Research: In the Mendel Family Library, on a desk in the rear of the room.
Effect: Research damage bonuses are increased by 60%.

Electric Flesh: In the Projection Booth upstairs in the Fleet Hall Theatre. It's only accessible after completing Cohen's masterpiece.
Effect: Reduces electric damage by 75% and increases your outgoing electric damage by 30%.

Electric Flesh 2: In Fontaine's Apartment, on the desk in his upstairs study.
Effect: Reduces electric damage by 100% and increases your outgoing electric damage by 60%.

Frozen Field: Search the corpse of Martin Finnegan inside the Frozen Tunnel.
Effect: Reduces cold damage by 15%. Wrench damage does an extra 10 points of cold damage and has a 10% chance of freezing enemy.

Frozen Field 2: On the desk in the Central Core, outside Andrew Ryan's Office.
Effect: Reduces cold damage by 30%. Wrench damage does an extra 20 points of cold damage and has a 10% chance of freezing enemy.

Human Inferno: Available at a Gatherer's Garden vending machine starting in the Arcadia area.
Effects: Reduces heat damage by 20%. Increases heat damage you inflict by 30%, burning monsters take damage at a 30% higher rate.

Human Inferno 2: Available at a Gatherer's Garden vending machine starting in the Point Prometheus area.
Effects: Reduces heat damage by 40%. Increases heat damage you inflict by 50%, burning monsters take damage at a 50% higher rate.

Photographer's Eye: In the bunk room of the wine cellar in Farmer's Market.
Effect: All research photo scores are increased by 10%.

Photographer's Eye 2: Receive for reaching Research Level 2 with Rosie.
Effect: All research photo scores are increased by 15%.

Static Discharge: In the Surgery Foyer, near the pool of water, near Dr.Steinman's lab.
Effect: When struck by a melee attack, the player emits an electrical burst that does 30 points of damage and includes a 15% chance of causing a shocked state.

Static Discharge 2: Receive for reaching Research Level 4 with Leadhead Splicers.
Effect: When struck by a melee attack, the player emits an electrical burst that does 50 points of damage and includes a 25% chance of causing a shocked state.

Wrench Jockey: In the Kure All area of Medical Pavillion. Crawl through the ventilation shaft near the floor to reach the small secret room.
Effect: Wrench damage increased by 350%.

Wrench Jockey 2: Receive for reaching Research Level 2 with Bouncer.
Effect: Wrench damage increased by 550%.

Wrench Lurker: In the Lower Wharf, on the edge of the walkway near the Gene Bank and Gatherer's Garden machines.
Effect: Wrench damage is increased by 150% versus unaware or shocked opponents. Also quiets your footsteps.

Wrench Lurker 2: Available at a Gatherer's Garden vending machine starting at Olympus Heights.
Effects: Wrench damage is increased by 200% versus unaware or shocked opponents. Also quiets your footsteps.

Gaining the achievements which involve Cohen can involve going through the games twice if not careful!
When you complete Cohen's Masterpiece and he comes down the stairs, go up and get what is needed from the room he was in earlier then head back to the masterpiece. Cohen will be admiring the artwork, SAVE the game here. Once saved KILL Cohen and photograph his body for that achievement, then just simply reload where you just saved and continue the game letting Cohen live so you can gain access to his apartment all in one fowl swoop.
DaveQ